Features of Interspecific Contacts and Hybridization of Ground Squirrels (Marmotinae, Sciuridae, Rodentia) in Mongolia.

Using molecular genetic methods, we investigated the secondary contact zones of two pairs of species of ground squirrels of Mongolia. In common colonies of marmots M. sibirica and M. baibacina, we revealed a high frequency of occurrence of hybrid individuals that were viable and fertile. A hybridization between S. alaschanicus and S. pallidicauda was sporadic in nature. The hypothesis about an extensive hybrid zone in these species of ground squirrels was not confirmed. An occupation of suboptimal biotopes by individuals of different species was the main factor contributing to hybridization in both case. The complex social behavior in marmots affected on the localization and diffusion of the hybridization process.

[Phylogeny of genus Spermophilus and position of Alashan ground squirrel (Spermophilus alashanicus, Buchner, 1888) on phylogenetic tree of Paleartic short-tailed ground squirrels].

Phylogenetic relationships within a group of Paleartic short tailed ground squirrels (Spermophilus), recently defined as genus, are not sufficiently clear and need a critical revision. Interspecies hybridization, found in Eurasian Spermophilus, can affect the results of reconstruction of molecular phylogeny. Alashan ground squirrel position on the phylogenetic tree needs clarification. We analyzed eight nucleotide sequences of cytb gene of S. alashanicus and 127 sequences of other Spermophilus species form GenBank. S.alashanicus and S. dauricus close phylogenetic relationship, and their affinity to ancestral forms of the group are revealed. Monophyly of Colobotis subgenus was confirmed. Paraphyly of eastern and western forms of S. relictus was shown.